Configuration of return-path

[RemiCollet]

Thunderbird always uses the sender address (From) as the return-path ("MAIL FROM:" in SMTP protocol)

With recent new legal requirements (at least in France), this MUST be validated by the SMTP server

Ex:

• smtp.orange.fr only accepts mail from *@orange.fr
• mail.gandi.net, when user is foo@domain.tld, only accepts mail from foo@domain.tld

This makes it impossible to use aliases for a personal domain

Proposal: allow to use SMTP user login in mail envelope (in "MAIL FROM:" for SMTP protocol, so as return-path) instead of profile email (sender)

I have written a small patch: https://rpms.remirepo.net/temp/remi.patch

Of course, this is only a prof of concept, unsuitable for everyone, and requires some config option for the SMTP server.

I'm building Thunderbird with this patch and I've been using it for weeks, it works.

Sent email has return-path set to my ISP address, and "From:" to my alias.

I think this conforms to the mail protocol.

[Jon]

Thanks for submitting an idea to the Mozilla Connect community! Your idea is now open to votes (aka kudos) and comments.

[MattAuSupport]

No, Thunderbird prefers the reply-To: header if it is set,  using the from: is actually a fallback position.

Thunderbird uses identities to select the correct SMTP server for the email reply function.  But if there is no identity for the account,  then the default is used.

Is a patch really required,  or is correct setup going to address the issue? 

[RemiCollet]

They are 2 distinct fields with different purposes.

The Reply-to (functional field) is information inside the envelope and does not hide the original sender, it is only used by mail clients when the reply function is called

The Return-path (technical field) is outside the envelope, used by SMTP protocol.

So yes, the patch is required, for now, there is no setup option for this

The goals of using aliases (identities) are:

• be able to always keep the same address, even when changing ISP
• be able to use some project-related addresses when working on a project (ex: @php.net, @fedoraproject.org, @mozilla.org...)